In recent years, people's demand on wireless broadband services keeps growing. Wireless access at anytime and anywhere becomes an inevitable trend with applications of popular networks such as microblog and Social Networking Services (abbreviated as SNS) and wide uses of smart phones such as Apple and Android. For a Universal Mobile Telecommunication System (abbreviated as UMTS) or a gradually commercialized Long Term Evolution (abbreviated as LTE) or Wireless Local Area Networks (abbreviated as WLAN) hotspots throughout cities, an growing requirement on mobile data traffic caused by increasing access users or prolonged online time leads to an increasing burden on the access network and a requirement on an increasing bandwidth, and the problem needs to be addressed.
Since new spectrum resources are almost allocated and it is unlikely to get a quota, it is not realistic to solve the above problem by seeking for new allocated spectrum resources. Therefore, improving spectrum utilization and increasing system capacity are preferred solutions for the above problem.